What are the divisors of 2911?

1, 41, 71, 2911

There is a total of 4 positive divisors.
The sum of these divisors is 3024.
The arithmetic mean is 756.

4 odd divisors

1, 41, 71, 2911

How to compute the divisors of 2911?

A number N is said to be divisible by a number M (with M non-zero) if, when we divide N by M, the remainder of the division is zero.

$N mod M = 0$

Brute force algorithm

We could start by using a brute-force method which would involve dividing 2911 by each of the numbers from 1 to 2911 to determine which ones have a remainder equal to 0.

$Remainder = N - (M \times ⌊ \frac{N}{M} ⌋)$

(where $⌊ \frac{N}{M} ⌋$ is the integer part of the quotient)

2911 / 1 = 2911 (the remainder is 0, so 1 is a divisor of 2911)
2911 / 2 = 1455.5 (the remainder is 1, so 2 is not a divisor of 2911)
2911 / 3 = 970.33333333333 (the remainder is 1, so 3 is not a divisor of 2911)
...
2911 / 2910 = 1.0003436426117 (the remainder is 1, so 2910 is not a divisor of 2911)
2911 / 2911 = 1 (the remainder is 0, so 2911 is a divisor of 2911)

Improved algorithm using square-root

However, there is another slightly better approach that reduces the number of iterations by testing only integers less than or equal to the square root of 2911 (i.e. 53.953683840865). Indeed, if a number N has a divisor D greater than its square root, then there is necessarily a smaller divisor d such that:

$D \times d = N$

(thus, if $\frac{N}{D} = d$ , then $\frac{N}{d} = D$ )

2911 / 1 = 2911 (the remainder is 0, so 1 and 2911 are divisors of 2911)
2911 / 2 = 1455.5 (the remainder is 1, so 2 is not a divisor of 2911)
2911 / 3 = 970.33333333333 (the remainder is 1, so 3 is not a divisor of 2911)
...
2911 / 52 = 55.980769230769 (the remainder is 51, so 52 is not a divisor of 2911)
2911 / 53 = 54.924528301887 (the remainder is 49, so 53 is not a divisor of 2911)